The present invention relates to heat sinks for use in portable electronic devices for disposing of the heat generated by an electronic component of the device.
The term "aluminum" as used herein includes pure aluminum and aluminum alloys.
With portable electronic devices including, for example, notebook personal computers, laptop personal computers and other portable computing devices, it is necessary to remove the heat generated by electronic components such as microprocessor unit (MPU).
For example, notebook personal computers generally comprise a thin housing having a keyboard, and a display device which is free to open or close relative to the housing. Arranged in the housing are an MPU and an aluminum or like metal plate disposed below the keyboard and serving as an electromagnetic shield.
U.S. Pat. No. 5,513,070 discloses the following structure for removing heat from the MPU for use in such notebook computers. A circuit board provided with an MPU on its underside is formed with heat channels extending from the underside to its upper side. The MPU is thermally connected by the heat channels to an aluminum block mounted on the upper side of the circuit board. A tubular heat pipe has one end attached to the aluminum block and the other end connected to a metal plate disposed below the keyboard and serving as an electromagnetic shield. The heat generated by the MPU is transferred through the heat channels to the aluminum block and further through the heat pipe to the metal plate, and released from this plate.
It is strongly desired that notebook computers and like portable electronic devices be compacted and have reduced weight since they are intended chiefly for portability. However, the heat sink structure described requires the aluminum block and tubular heat pipe, is therefore relatively bulky and heavy, and has the problem that the electronic device can not be made more compact and less heavy in its entirety. The heat generated by the MPU is transferred to the working liquid by way of the heat channels, aluminum block and tubular wall of the heat pipe, so that the disclosed structure has another problem of failing to effect efficient heat transfer from the MPU to the working liquid and being low in heat disposal effect.